Magnetoresistance is the ability of a material to change its electrical resistance when exposed to an external magnetic field. This ability may be taken advantage of to provide, among other things, sensors for detecting magnetic field intensity. Anisotropic magnetoresistance (AMR) is a form of magnetoresistance where the change in resistance of a material depends upon the angle between the direction of magnetization and the direction of current flow in the material. Typically, the resistance of an AMR material will be a maximum when the magnetization of the material is in the same direction as the current. To achieve linear operation in an AMR sensor, an angle may need to be maintained between the direction of magnetization with no external magnetic field applied (i.e., the easy angle) and the current in the AMR element. Most modern AMR sensors use “barber pole” structures to provide the desired current angle. Typically, an angle of around 45 degrees is used.
As with any electrical device, there is a need for new and improved AMR sensor architectures. There is also a need for new techniques for efficiently and/or inexpensively fabricating AMR sensors. Techniques are also needed for producing AMR sensors that are capable of high performance operation.